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Developing efficient and durable oxygen evolution reaction (OER) catalysts holds great promise for green hydrogen production via seawater electrolysis, but remains a challenge. Herein, we report a Co-doped Ni3S2 nanosheet array on Ni foam (Co-Ni3S2/NF) as a high-efficiency OER electrocatalyst for seawater. In alkaline conditions, Co-Ni3S2/NF requires an overpotential of only 368 mV to drive 100 mA·cm−2, superior to Ni3S2/NF (385 mV). Besides, it exhibits at least 50-h continuous electrolysis. [ABSTRACT FROM AUTHOR]

Sonicated mesoporous BiVO 4 /TiO 2 heterojunctions were recorded for highly efficient photodegradation of rhodamine B dye and production of hydrogen gas. The heterojunction structures were characterized by XRD, DRS, FTIR, BET, FESEM, HRTEM and PL. The efficiency of the radiation power of ultrasound waves [50–300 Watt/cm2] on dye degradation and efficiency of hydrogen production was established. BiVO 4 shifts the photocatalytic response of titania toward visible region. The photocatalytic efficiency of RhB removal on the nanocomposites surface containing 10 wt% BiVO 4 is 0.021 min−1 tenfold higher than that of bare TiO 2 (0.0023 min−1). The optimum concentration of BiVO 4 was found to be 10 wt% that generate hydrogen gas with rate equal to 14.3 mmolg−1h−1. Ultrasound radiation is a prime key in reducing the population of particle aggregates and reflects a strong interaction between BiVO 4 and TiO 2 nanoparticles that results in lowering the electron-hole pairs recombination rate and increase the concentration of active sites and amount hydrogen evolved. The production of hydroxyl and superoxide radicals suggest a direct Z-scheme mechanism for explaining the high photocatalytic reactivity of sample. [Display omitted] • Novel BiVO 4 /TiO 2 nanocomposites were synthesized by sonochemical route. • A strong chemical interaction between BiVO 4 and TiO 2 nanoparticles. • Z-electron transfer scheme is purposed. • A stable photocatalyst for five consecutive cycles. [ABSTRACT FROM AUTHOR]

In the recent years, direct Z-scheme heterojunctions exhibit an exceptional reactivity in various photocatalytic processes. Hybrid visible light driven photocatalyst consisting of semiconducting metal oxide and conducting polymer have immense capability of destruction of various organic pollutants and production of hydrogen gas as alternative renewable energy source. Herein, a novel hybrid polyaniline/ZnO heterojunction were synthesized by coupling sol-gel and oxidative polymerization of aniline in ultrasonic bath of various intensities for removal of fluorescein dye and producing large amount of hydrogen gas under visible light source. Particularly, the amount of polyaniline plays a pivotal role in optimizing the amount of hydrogen gas produced. The change in the diffraction pattern of Wurtzite ZnO nanoparticles and the remarkable reduction of PL signal intensity suggest the construction of direct Z-scheme heterojunction. The photocatalytic hydrogen production rate estimated on the optimized sample using methanol as scavenger is 9.4 mmolh−1g−1 which is higher than that of bare ZnO nanoparticles. The sample containing 5 wt% polyaniline exhibits photocatalytic degradation rate of fluorescein dye 0.021 min−1 which is ten folds higher than that of bare ZnO. The results of our research work indicate that polyaniline is efficiently enhances the light absorption and providing an additional electrons that combine with H+ to produce H 2 -gas. [Display omitted] • Novel polyaniline/ZnO were synthesized by sonochemical route. • Positive shift of the photocatalytic response to visible region. • Exceptional photocatalytic hydrogen evolution. • High stability for five consecutive cycles. [ABSTRACT FROM AUTHOR]